ind the sum of first 22 terms of an AP in which d- 7 and 22nd term is – InterviewSolution

1.	ind the sum of first 22 terms of an AP in which d- 7 and 22nd term is 149
Answer» Given d = 7,22nd term =149 ,⇒ a+21d = 149⇒a+21(7) = 149⇒a+147 = 149⇒a=149-147=2Sn = (n/2)(2a+(n-1)d)S₂₂ = (22/2)(2×2+(22-1)7)S₂₂ = 11(4+21(7))S₂₂ = 11(4+147)S₂₂ = 11(151)S₂₂ = 1661.

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